Apparatus for servicing airplane propellers



y 1952 J. F. SWEENEY ETAL 2,602,217

APPARATUS FOR SERVICING AIRPLANE PROPELLERS Filed May 9. 1949 4 Sheets-Sheet 1 J0 [iii 6.272%);

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[I'M 2.72 A Mac/0y July 8, 1952 J. F. SWEENEY ET AL APPARATUS FOR SERVICING AIRPLANE PROPELLERS 4 Sheets-Sheet 2 Filed May 9, 1949 a? 62% JPMW y 1952 J. F. SWEENEY ET AL 2,602,217

APPARATUS FOR SERVICING AIRPLANE PROPELLERS FiledMay 9, 1949 4 Sheets-Sheet 3 J y 1952 J. F. SWEENEY ET AL 2,602,217

APPARATUS FOR SERVICING AIRPLANE PROPELLERS Filed May 9, 1949 4 Sheets-Sheei 4 .IIIL

X/i/f /P/Q) 0/24 2?! cin eefiey Patented July 8, 1952 APPARATUS FOR SERVICING AIRPLANE PROPELLERS John F. Sweeney, Edward T. Able, and Irwin A. MacKay, Denver, 0010., assignors to B. K.

Sweeney Manufacturing Company, Denver,

0010., a corporation of Colorado Application May 9, 1949, Serial No. 92,126

6 Claims.

This invention relates to apparatus for servicing airplane propellers, and more particularly to servicing apparatus including means for lifting and handling, and for loosening and tightenlug nuts which retain propellers on their motor shafts.

Airplane propellers require frequent servicing and for this purpose must be removed from their motor shafts, carried to a work shop, returned to the field or hangar, and replaced on the motor shafts of the planes. Propellers weigh as much as 1000 to 1200 pounds, and due to their shape and weight the servicing and handling present certain difliculties which it is the object of our invention to overcome.

The main object of our invention is to produce apparatus which is adapted to be securely fastened to a propeller whereby the servicing device and the propeller may be lifted and moved without injury to the propeller.

Another object of the invention is to produce servicing apparatus provided with, pivotally mounted means whereby the propeller is supported and may swing from vertical to horizontal position, and vice versa, While the servicing apparatus is suspended in supporting position by a lifting crane or other suitable mechanism.

Another object is to produce apparatus of the character described in which the axis of said pivotally mounted means intersects the center of gravity of the propeller to which. the servicing device is secured, whereby the propeller is automatically balanced in either vertical or horizontal position.

Another object is to produce servicing mechanism of the character described which is designed to cooperate with a wrench for loosening and tightening the nuts which hold the propeller on its motor shaft, and to serve as anchor means for the wrench, including means for retaining the wrench in operative position on such anchor means. The wrench anchoring means of our invention may be used separately for the purpose of anchoring the wrench, or it may be part of means for lifting and handling the airplane propeller.

Another object of the invention is to provide in the such servicing apparatus, means for locking the pivotally movable parts to prevent relative movement thereof. Such locking means may be provided for locking the parts when the propeller is being supported in vertical position, or in either its vertical'or horizontal position.

By vertical position of the propeller, we mean that the body and blades as a whole are 2 vertically disposed and the axis of the hub extends in a horizontal plane. To support the propeller in such vertical position, the anchor means of the apparatus has its face vertically disposed and at right angles to the axis of the propeller hub.

In the drawings:

Fig. 1 is an elevational view of servicing apparatus embodying our invention, showing the anchor means thereof with its face vertically disposed for attachment to an airplane propeller when the propeller is in vertical position.

Fig. 2 is a side elevational view of the servicing apparatus shown in Fig. 1, on an enlarged scale, showing the anchor means attached to the hub of a propeller, the propeller blades being broken away.

. Fig. 3 is a view similar to Fig. 2, but showing the anchor means in horizontal position, as it appears when the propeller to which it has been secured is horizontally disposed and the axis of its hub is in a vertical plane. 1

Fig. 4 is an elevational view of servicing apparatus embodying our invention, similar to that of Fig. 1, but showing the anchor means with its face horizontally disposed, attached to a propeller hub, with a wrench in position .on the anchor means, as the parts appear when the propeller as a Whole is horizontally disposed.

Fig. 5'is a transverse vertical sectional view, partly in elevation, taken in the plane of the line 55 of Fig. 4, but somewhat enlarged.

Fig. 6 is a plan view of anchor means which constitute part of our servicing apparatus.

Fig. 7 is a longitudinal sectional view of the anchor means of Fig. 6, taken in the plane of the line 1--1 of Fig. 6.

Fig. 8 is a plan view of a modified form of anchor means which constitute part of the servicing apparatus.

Fig. 9 is a longitudinal sectional view of the same taken in the plane of the line 9- -9 of Fig. 8.

Fig. 10 is a plan view of another modification Fig. 14 is a transverse sectional view taken in the plane of the line i4l4 of Fig. 13.

In the drawings, we have shown the preferred embodiment of our apparatus, and three different forms of anchor means used therein. These anchor means may be employed separately to function only as anchor means for a wrench When it is desired to work on the nut or nuts which hold the propeller on its shaft, or said anchor means may be part of the handling and lifting mechanism of our apparatus. The essential parts of the preferred form of servicing apparatus are (l) the anchor means which are securely but removably fastened to an airplane propeller and which serve to support and anchor a wrench during that part of the operation when;

it is necessary to loosen or tighten the nuts which retain the propeller on its motor shaft; (2) specially shaped lift arms rigidly connected to opposite ends of the anchor means and pivotally connected to a yoke; (3) said yoke comprising a pair of curved arms pivotally connected at one of their ends to said lift arms and connected together at their other ends by a cross piece which is adapted to be engaged by a crane or other suitable mechanism for lifting the servicing apparatus and attached propeller.

Referring first to Fig. 1 to 5, inclusive, an airplane hub is indicated at H), its center bore at ll, blade sockets (broken away) at [2, airplane -motor shaft at i3 and a nut for retaining the hub on the shaft at it. These are conventional parts of airplane propellers which vary in form and construction. The servicing apparatus of our invention likewise is varied in construction to some extent to accommodate itself todifferent forms of airplane propeller hubs and blades. For this reason it is necessary to 'provide'dilferent forms of anchor means adaptedto be secured to the different airplane propellers to be serviced. In Figs. 1 to 5, inclusive, the anchor device is indicated as a whole at 55, and has a body centrally apertured, adapted to be seated on the exposed face of an airplane propeller hub, concentric therewith, and provided with means for securely fastening the anchor means and 'hub together. A pair of lift arms I6, I6, are adapted to be rigidly connected to opposite sides f the anchor means 1'5. For convenience in shipping, the lift arms are made separately from the anchor means l5, but when assembled they are in effect a single unit. Each of the arms i6 consists of an elongated member 17, and end. 53 extending at an angle from one end of the member H, and an end l9 extending at anangle from the other end of the member ll, parallel with but in a direction opp site to that of the end is, as shown in Fig. 4. The arms [5, are identical but when secured at their ends L8 to opposite sides of the anchor means 15, their elongated portions I? extend in slightly divergent directions with respect to each other. Assuming the faces of the anchor means 15 to be horizontally disposed, as shown in Fig. 4, the lift arms I6 extend downwardly so that the axis of their outwardly extending ends 6 9 intersects the center of gravity'of the propeller hub IE3.

The lifter yoke comprises two curved arms 23 resembling an elongatedC when viewed in side elevation, and a connecting cross member 2| of any suitable construction secured to the upper ends of the arms 28, adapted to be engaged through the eyelet 22 by a crane or other suitable lifting mechanism. The curved armsv 29 are relatively thin, in cross section, and when pivotally connected at their lower ends to' the lift 4 arm ends I9, said arms 20 are substantially parallel to the lift armmembers ll.

The pivotal connection between the lift arms It and lifter yoke arms 20 is designated 23. It comprises a reinforcing bead 24 formed on the lower end of. each; arm 22, surrounding a hole 25 through the arm 28, the faces of the bead 24 projecting beyond the side surfaces of the arm 26 and at an angle thereto; that is to say, the axis of the hole 25 coincides With the axis of the lift arm end l9, and the faces of the reinforcing bead 24 are perpendicular to the axis of the hole 25 and at an angle to the flat side surfaces of the C-arins 2B which are slightly inclined toward each other as shown in Figs. 1 and. The ends IQ of the lift arms it have reduced portions which extend through the holes 25 of the C-arms 20 and are pivotally retained by a bolt 26 which extends through a cap washer '21 into the reduced portion of the lift arm end I9.

At the upper ends the C-arms 26 are provided with apertures 28 to receive the ends of the cross piece 2| which are rigidly connected thereto in any convenient manner. For certain purposes these parts may be made separately but when assembled the anchor means Hi, the lift arms I6 and thelifter yoke 2!], 2!, are rigidly connected together excepting at the connections 23 between the ends it of the lift arms 16 and the lower ends of the C-arms 29, which afford pivotal movement between the lift arms [15 and the C-arms 2B.

In Figs. 6 to 12, inclusive, are. shown three different forms of anchor means such as referred to heretofore by the numeral i5, and these will be described now in detail. Each of these forms is adapted to be used separately only as anchoring means for a wrench or to be connected to lift arms 6 to become part of the handling and lifting means of our servicing apparatus.

Referring to Figs. 6 and 7, the anchor means there shown comprise an outer plate 30, an inner plate 3!, both centrally apertured and connected together, thus providing a concentric opening 33 adapted to register with the bore 1! of the propeller hub Iii. The outerplate 32 is provided with recesses 34 adapted to receive and anchor parts of a wrench 35 (see Fig. 2). Said plate is designed to support the wrench in operative position When it' is desired to loosen or tighten the nut is on the motor shaft l3 whereby the propeller hub is held on the shaft. The outer anchor plate 3.2 is provided with oppositely extended portions which terminate in shoulders 35 provided with recesses 31. The recesses 31 are axially aligned and arranged to receive the reduced portions of the ends 18 of the lift arms it which are retained therein by any suitable means as indicated at 38 in Fig. 4:.

The inner plate 3| is so called because it constitutes that face of. the anchor means which contacts the face of the propeller hub when the apparatus is fastened to the hub Ill. Said inner plate 3] is provided witha plurality of holes 39 adapted to receive screws or bolts whereby the anchor means is securely but removably-fastened to the face of the propeller hub.

Referring to the modified form of anchor means shown in Figs. '8 and 9, those parts of the construction whichare similarto the parts described in connection with Figs. 6 and 7 have been similarly designated. This form of construction is particularly adapted to be mounted-on propellers provided with screw threads for engaging a. partfof the anchor means; In this embodiment, the inner plat'eis designated 48, and is provided. with holes 4l.-'.. The outer plate. 30 has lugs. 30. ,;A separate ring .o'rnut 42 has external this modification, the anchor means comprises an outer plate 45 integral with ,a sleeve 46 which :is concentric with the bore of the propeller hub I; Said plate 45 has oppositely extendingportions provided with wrenchseating recesses 41,

and shoulders 48 with recesses 49, forreceiving :the ends- 18 of lift arms [6, asheretofore des scribed. a

The special feature of this anchor device is the arrangement whereby the anchorplate is secured to the propeller blade sockets 12. This feature comprises a pair of extensions 50 on the plate 45 located radially opposite each-other or otherwise as required by the location of the propeller blade sockets. The extensions 50 terminate in jaws each comprising a horseshoe shaped body having two pivotally mounted arms 52. Each arm 52 is pivotally connected by a pin or rivet 53 to the horseshoe body, so that the gripping end 54 can swing outwardly away from its mateand thus permit the jaws 5| to be. placed over "a propeller blade socket. When in position the gripping ends 54 are moved toward each other and a pin 55 is inserted through apertures in the body of the jaw 5-! and in the arm 52 as shown in Fig. 13, whereby separation of the gripping ends 54 is prevented.

Preferably the inner surfaces of the arms 52 and gripping ends 54 are lined with rubber belting 56 or other resilient material which prevents them-from chafing the blade sockets:

In Figs. 13 and 14 are .shown details of the locking mechanism attached to each of. thecarms of the lifter yoke for cooperation with a part on the adjacent lift arm I6 for locking the pivctally connected parts of the servicing apparatus together and preventing pivotal movement between themat either limit of their movements. Said lock mechanism comprises. a, pair of spaced apart, parallel plates 51 cut away to provide a slot 58 open at one end, adapted to receive a pin 59 fixed on the number ll of thelift arm IS. The plates 51 are riveted or otherwise secured together in spaced relationship as shown and are secured by rivets or other suitable means to the C-arms 20. Between the plates 51 is pivotally mounted at 60 a bell crank lever 6|, one arm of which is hook shaped as indicated at 62. The

arm '52 engages the pin 53 on the lift arm when the parts are in locked position. A coiled spring 63 secured to the lever 6 land to one of the plates 51 retains the parts inlo-cking position. When it is desired to release the latching device 62 from the'pin 59, a pull cord-64 attached to the exposed end- 65 of the bell crank lever may .beactuated 'to pivotally move the lever and release :said hook device '62. Thelockingdevice described :is one designed to hold the pivotally connected parts of the apparatus against relative movement; when the propeller is in vertical position, but similar locking mechanism may be positioned'to function for holding said parts when the propelle is in horizontal-position.

It will be understood that each 'of the anchor of the propeller.

'6 means described herewith is provided with a bore concentriclwi'th the bore of the propeller hub, whereby the tool employed to work on nuts .on the airplane motor shaft can be' insertedv through the anchor means and be actuated inside of the propeller hub while the anchor for. the tool serves as the connecting means between our servicing apparatus and. the propeller. An example of how this construction serves is shown in Figs. 4 and 5, where the wrench 35 is supported" on the anchor means I5 and the latter is securely fastened to the propeller hu'b it -by boltsfifi. Theinternal construction of the wrench 35 need not be shown in detail; Any power multiplying wrench mechanism may .be. used. In the wrench 35, a train of gears is-employed to provide. the desired gearratio between the-power input shaft 68 and the power? output shaft 69. Internal splines in said shaft 69 in this embodimenttengage external splines 10 on the'part H .of the socket 12. The socket 12 is shaped as indicated at 13 to fit the castellated nut. I4 which holds the propeller hub 10 on its shaft l3. A=handle 14 engages the shaft 58 of the wrench for rotating said shaft. 7

The. wrench 35 is held on the anchor means l5 by-anchor pins 15, one of which may be selflocking and the other locked with a thumbscrew I6. 11 indicates depending pins on thewrench which seat in the recesses 34 or 41 of theanchormeans, whereby the wrench is properly positioned on said anchor means.

Operation-When an airplane propeller requires servicing, our servicing apparatus is moved into juxtaposition to the propeller by means of a lifting crane or other suitable mechanism which engages the eye 22 of the cross piece 2|. The anchor means [5 is securely fastened to the propeller hub in or to the blade sockets l2 depending .on the type of anchor. means selected from the three shownin Figs. 6 to 12, inclusive. At this stage of the operation, inner and-"outer anchor plates such as the plates 30 and 31, Figs. 6 and 8, or the outer plate 45, Fig. 10, will be vertically disposed, with the opening 33 concentric with the bore of the propeller hub and the axis in a substantially horizontal plane. The members ll. of the lift arms [6 will also extend horizontally while the carms remain substantially vertical as shown in Fig. 2. It will be noted that the shape of the C-arrns is such that they do not interfere with the propeller blades eventhough the ends of said arms'20 are pivotally connected to the lift arms IS in an axial line which intersects the center'of gravity of the propeller hub regardless of the position The locking means automatically functions to prevent relative movement between the pivotally connected parts, when the propeller has been moved to either vertical or horizontal position.

Next the wrench35 is mounted on the anchor means [5, and in order to prevent the; wrench from falling off the anchor plate, the fastening means 15 and 16 are employed. Then the wrench is manually operated to loosen the-nut I4 or other nuts which may hold the propeller on its shaft, and when the propeller is ready to be removedfrom the shaft the servicing apparatus, as a whole, actuated by a lifting crane (not shown), moves the propeller forwardlyoff its shaft and clear thereof. The wrench may be removed from the anchorplate before the propeller is moved off its shaft, or it may be left on the anchor plate during the propeller moving operation, as preferred. After the propeller has cleared the shaft, the locking mechanism. may be actuated by thepull cord 64- to release the latching device 62 and allowthepropeller to be swung into horizontal position, as shown in Fig. 3 (where the wrench is still on the anchor means), as is most convenient for transporting the propeller on a truckto the workshop for service.

...Usually the servicing apparatus is removed from the propeller while itis being. serviced. Aftenthe servicing has been completed, the anchor .means of the, servicing apparatus is reattached to the propeller hub (or blade sockets) and the apparatus and propeller are carriedback tothe airplane. Before attempting to remount the propeller on its shaft, itis most convenient to position the wrench onthe horizontally dis,-

.posed anchor means, secure the fastening devention comprises a rigid yoke consisting of the G-arms 2B and connecting piece 2| which may be termed an outer yoke, and a second rigid yoke consisting of the lift arms l6 and intermediate anchor means i which may be termed an inner yoke in the sense that it is movable. between the C-arms of the outer yoke. The inner and outer yoke members are pivotally connectedv together at 23 as heretofore explained, and the relationship between the pivotal connection and that part of the anchor means l5 which is fastened to the propeller hub is such that the axis of the pivotal connection intersects the center of gravity of the propeller. This arrangement insures efdcient handling of the propeller with a minimum of effort.

The dual function of the anchor .means as anchor means, per se, or as part of the inner yoke is another important feature of our invention. Heretofore the services of a number of workmen were required to hold a wrench in proper positionv relatively ,to the. propeller and to operate it for thepurpose. of loosening or tightening the retaining nut or nuts. By employing our anchor means, separately or as part of the apparatus as a whole, the wrench is supported and retained in operative position on the anchor .means for efficient operation of the wrench. 1

Changes may be made in the form and dimensions of our apparatus, and in details of construction, without departing from the scope of our inventionas defined by the appended claims.

8 comprising a ring on the anchor, said ring having screw threads adapted to engage threads on the propeller hub, means on the wrench-engaging face of the anchor for fastening a wrench on said anchor, and an outer yoke member having spaced apart arms pivotally connected at their free ends to the lift arms of theinner yoke member, said anchoropening affording access to the propeller hub for operation thereon by a wrenchwhen positioned on said anchor.

2. Apparatus for servicing airplane propellers, comprising an inner yoke member including a pair of lift arms and a centrally located wrench anchor rigidly connected to said arms, the wrench anchor having oppositely located wrench-engaging and propeller-engaging faces, a concentric opening in the anchor extending from one of said faces to the other, means for removably connecting the anchor to a propeller comprising a pair of gripping jaws on said anchor adapted to grip propeller blade sockets, means on the wrench-engaging face of the anchor for fastening a wrench on said anchor, and an outer yoke member having spaced apart arms pivotally connected at their free ends to the lift arms of the inner yoke member, said anchor opening affording access to the propeller hub for operation thereon by a wrench when positioned on said anchor.

'3. Apparatus for servicing airplane propellers, comprising an inner yoke member including a .pair of lift arms and a centrally located wrench anchor rigidly connected to said arms, Wrench anchor having oppositely located wrench-engaging and propeller-engaging faces, a concentric opening extending from one of said faces to the other, each of said lift arms, consisting of an elongated body having oppositely directed end portions parallel to each other, means for removably connecting the anchor to a propeller, means on the wrench-engaging face of the anchor for fastening a wrench on said anchor, and an outer yoke member having spaced apart arms pivotally connected at their free ends to end portions of said lift arms, said propeller when attached to the anchor of the inner yoke member being swingable to vertical or horizontal position without contacting said outer yoke wrench wrench-engaging and propeller-engaging faces,

a concentric opening extending from one of said faces to the other, means for removably connecting the anchorto a propeller, means on the wrench-engaging face of the anchor for fastening a wrench on said anchor, and an outer yoke member having spaced apart arms pivotally connected attheir fre'e'ends to the lift arms of the inner yoke member, said outer yoke member arms being. substantially C-shaped, said propeller when attached tothe anchor of the inner yoke member being swinga'ble to vertical or horizontal position without contacting said outer yoke member,2and said anchor opening affording access to the propeller hub for operation thereon by a wrench when positioned on said anchon 5. Apparatus for servicing airplane propellers, comprising an inner yoke member including a pair of lift arms and a centrally located wrench the 9 anchor rigidly connected to said arms, the wrench anchor having oppositely located wrench-engaging and propeller-engaging faces, a concentric opening extending from one of said 7 faces to the other, means for removably connecting the anchor to a propeller, means on the wrench-engaging face of the anchor for fastening a wrench on said anchor, an outer yoke member having spaced apart arms pivotally connected at their free ends to the lift arms of the inner yoke member, said propeller when attached to the anchor of the inner yoke member being swingable to vertical or horizontal position, and said anchor opening affording access to the propeller hub for operation thereon by a wrench when positioned on said anchor and locking means on one of said yokes adapted to engage cooperating means on the other for automatically locking the yokes together and preventing relative movement of the pivotally connected parts when the propeller is in a predetermined position.

6. Apparatus for servicing airplane propellers,

comprising an inner yoke member and an outer yoke member having spaced apart arms pivotally connected at their free ends to said inner yoke member, said inner yoke member including a pair of lift arms and a centrally located wrench r 10 anchor rigidly connected to said lift arms, the wrench anchor having oppositely located wrench-engaging and propeller-engaging faces, a concentric opening in the anchcor extending from one of said faces to the other, means for fastening the anchor to a propeller, and means on the wrench-engaging face of the anchor for fastening a wrench on said anchor, said anchor opening affording access to the propeller hub for operation thereon by a wrench when positioned on said anchor.

JOHN F. SWEENEY.

EDWARD T. ABLE.

IRWIN A. MAoKAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

